Synchronisation (XP Pro)

Synchronisation is working really well for teachers at our school, caching their network files to use at home is very useful. However, one of our notebooks complains that it can't synchronise three files, two being jpegs and the other a .pfl file. These files don't exist either on the notebook or on the user's network area. Any ideas where WindowsXP is holding this information? It would be nice to flush out this info so that the user gets a clean logon.